X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/ac0dcd3f05a8821d7ce042646472be1995a08042..c3da38a12a2372a7f6a48be97ebfd80aeceda828:/test/scripts/1990-TCP-Fast-Open/1990?ds=inline

diff --git a/test/scripts/1990-TCP-Fast-Open/1990 b/test/scripts/1990-TCP-Fast-Open/1990
index cbedd3622..80059e685 100644
--- a/test/scripts/1990-TCP-Fast-Open/1990
+++ b/test/scripts/1990-TCP-Fast-Open/1990
@@ -7,26 +7,53 @@
 # A packet capture on the loopback interface will show the TFO
 # option on the SYN, but the fast-output SMTP banner will not
 # be seen unless you also deliberately emulate a long path:
-# 'sudo tc qdisc add dev lo root netem delay 100ms'
+# 'sudo tc qdisc add dev lo root netem delay 50ms'
+# You'll need iproute-tc installed, for the tc command.
+# You'll need kernel-modules-extra installed, or you get
+# an unhelpful error from RTNETLINK.
+# To tidy up:  'sudo tc qdisc delete dev lo root'
+#
+# MacOS:
+# The kernel seems to have TFO enabled both ways as default.
+# There is a net.inet.tcp.clear_tfocache parameter
+## sysctl -w foo-val
+#
+# For network delays there is something called 'Network Link Conditioner'
+# which might do the job.  But how to manipulate it?
+#
+#
+# FreeBSD: it looks like you have to compile a custom kernel, with
+# 'options TCP_RFC7413' in the config.  Also set
+# 'net.inet.tcp.fastopen.server_enable=1' in /etc/sysctl.conf
+# Seems to always claim TFO used by transport, if tried.
+#
+sudo perl
+system ("tc qdisc add dev lo root netem delay 50ms");
+****
+#
+#
+# Disable the TFO blackhole detection, as we seem to be running foul of it.
+# If bitten, we see the expected EINPROGRESS for sendto, yet no TFO cookie
+# option on the SYN.
+#
+sudo perl
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 0 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
+****
 #
 # First time runs will see a TFO request option only; subsequent
 # ones should see the TFO cookie and fast-output SMTP banner
 # (currently on a separate packet after the server SYN,ACK but before
 # the client ACK).
 #
-# The client log => lint.ex  should have a "TFO" element.
-# Assuming this is the first run since boot, the a@test recipient will not.
-#
-# The server log <= line for b@test.ex  should have a "TFO" element, but
-# this will only be obtained when the above delay is inserted into the
-# loopback net path.
+# The client log => line  should have a "TFO" element.
+# The server log <= line for a@test.ex  should not.
 #
+# First clear any previously-obtained cookie:
+sudo perl
+system ("ip tcp_metrics delete 127.0.0.1");
+****
 #
 #
-# FreeBSD: it looks like you have to compile a custom kernel, with
-# 'options TCP_RFC7413' in the config.  Also set
-# 'net.inet.tcp.fastopen.enabled=1' in /etc/sysctl.conf
-# Untested.
 #
 exim -DSERVER=server -bd -oX PORT_D
 ****
@@ -36,10 +63,20 @@ Testing
 ****
 sleep 3
 #
+# The server log <= line for b@test.ex  should have a "TFO" element, but
+# this will only be obtained when the above delay is inserted into the
+# loopback net path.
+#
 exim b@test.ex
 Testing
 ****
 sleep 3
 #
+#
+sudo perl
+system ("tc qdisc delete dev lo root");
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 3600 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
+****
+#
 killdaemon
 no_msglog_check